Experiments carried out in this laboratory have shown that LAAM and congeners possess significant cardiovascular activity. Attenuation of sympathetic nervous system activity appears to contribute to the responses in intact animals. During the next year I plan to identify the separate components of the responses in intact animals. I also plan to monitor the cardiovascular responses to certain exogenous agents in animals which have been pretreated with LAAM (e.g. norepinephrine, digitalis). Finally, I plan to complete experiments designed to determine whether tolerance develops to the cardiac effects of LAAM.